Grinding apparatus



N0V- 13, 1956 R. c. NoRTHcUTT ET A1. 2,770,081

GRINDING APPARATUS Filed Jan. 8, 1954 Unit GRINDING APPARATUS Roy C. Northcutt and Joseph N. Staggs, Muncie, Ind., assignors to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Application January 8,1954, Serial No. 403,007

6 Claims. (Cl. 51-103) .ferent diameters on a shaft intended for use in a power transmission which has a gear fixed on the shaft for transmitting power through the transmission.

Previously in grinding such a shaft the end of the shaft was gripped in a collet or chuck for the purpose of drivingly rotating the shaft while the shaft was being ground by an abrasive grinding wheel. The particular portion of the shaft within the collet or chuck, of course, was not exposed so that it could be ground simultaneously with the rest of the shaft, and it was, therefore, necessary to grind the gripped part subsequently in a second grinding operation in which another part of the shaft was gripped by an appropriate chuck. Due to the two separate grinding operations, a certain amount of eccentricity developed between the surfaces separately ground, regardless of the best efforts to keep the surfaces absolutely concentric.

It is an object of the present invention to provide an apparatus and method for grinding such a power transmission shaft so that all of the diameters of the shaft can be simultaneously ground in a single operation.

In particular, it is an object of the invention Vto utilize the gear on the transmission shaft for driving the shaft as it is ground by the grinding wheel.

Still more particularly, it is an object to provide countershaft gearing including the transmission gear for driving the shaft as it is ground. It is contemplated that a gear may be iixed to the rotatable headstock of the grinding apparatus and that the countershaft gearing may be maintained in mesh with both the gear on .the headstock and the gear on the shaft for so rotating the shaft.

The invention consists of the lnovel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of a preferred embodiment, illustrated with reference to the accompanied drawing, wherein;

Fig. l is a plan view of a driving mechanism for a power transmission shaft in a grinding apparatus particularly adapted for such a shaft;

Fig. 2 is a side view, partially in section, of the driving mechanism shown in Fig. 1;

Fig. 3 is an end view of the mechanism shown in Fig. 1 and taken on lines 3--3 of Fig. 2; and

Fig. 4 is a schematic view showing the driving mechanism for a power transmission shaft particularly ,adapted for such a shaft.

The drawing is to be understood to be more or less of "a `schematic character for the purpose of illustrating and disclosing an exemplary form of the improvements contemplated herein, and in the drawing, like reference characters identify the same parts in the several views.

Referring particularly to Fig. l of the drawing, the illustrated grinding apparatus comprises, in general, a grinder or grinding wheel 10, a gear train 11, and workpiece support means 12 and countershaft support means 13.

, The workpiece support means A12 comprises a spindle States Patent *i or headstock 14 at one end and a mandrel or tailstock 15 at the other end, which is adjustable toward and away from the headstock for the purpose of rotatably mounting and positioning a transmission shaft or any other similar workpiece 16 in the machine. The center point of headstock 14 extends into a tapered end bore 17 of the shaft 16, and the center point of tailstock 15 extends into the hollowed end 18 of the shaft 16. A gear 19 is integrally formed on the transmission shaft 16 and a driving gear 20, which is of the same size as gear 19, is securely mounted on the spindle or headstock 14. The gear train 11 also includes a pair of pinion gears 21 and 22 mounted on a countershaft 23. The driving motion is transferred through the gear train 11 from the gear 20 to the gear 19 via the pinion gears 21 and 22. The pinion 21 is in mesh with the driving gear 20 at one end of the countershaft 23, and at the other end the pinion 22 is in mesh with the gear 19. Since gear 19 is the same `size as gear 20, and gear 21 is the same size as gear 22, the speed or number of revolutions of the transmission shaft 16 is the same as that of the headstock.

The countershaft support means 13 serves to maintain in position the countershaft 23 and the pinions 21 and 22 located at the opposite ends of the countershaft. The countershaft support means 13 comprises a U-shaped support 24 which has upwardly extending arms 25 and 26. The countershaft extends through the arms 25 and 26 and is rotatably mounted therein with the pinions 21 and 22, which are keyed or splined to the opposite ends of the countershaft.

The countershaft support means 13 also includes a brace plate 27 which has an elongated hooked side 28 and which is movably iixed to the U-shaped support 24 by two pairs of bolts 29 and 30 extending through slots 31 and 32 and a bed plate 33 having an elongated slot 34. A set of bolts 35 are provided for securely anchoring the brace plate 27 with respect to the bed plate 33. The elongated hooked side 28extends outwardly from the brace plate 27 and conforms to one side of the slot 34 cut in the bed plate 33. Tightening of the bolt 35 wedgingly engages the hooked side 34 of the brace plate 27 with the side of the slot 34. The slots 31 and 32 serve to permit the pinion gears 21 and 22 mounted on the countershaft 23 to be moved toward or away vfrom the gears 19 and 20 to provide proper mesh `of the gears, while the elongated slot 34 permits movement of the countershaft and pinion gears in either sideward direction.

The grinder 10 is actually a multi-diameter wheel that is set up for grinding simultaneously all the different diameter portions on the shaft 16, and comprises grind-1 ing surfaces 36, 37, 38, 3.9, 40, 41 and 42. With the exception of surface 40, the remainder are in direct contact with surfaces 43, 44, 45, 46, 47 and 48 on the transmission shaft 16. The grinder 10 is capable of being brought in and out of position orcontact with the shaft 16 whenever it is necessary or when a new workpiece or shaft is inserted in the workpiece support means 12 fo the ,purpose of being ground.

In operation of this grinding apparatus, a workpiece such as -a transmission shaft 16 is lirst rotatably vmounted in ythe machine. This is accomplished by placing the center point of the tapered end of the headstock 14 into the tapered center bore of shaft 16 and moving the center point of ythe tailstock 15 into the hollowed end 1S on the other end of the shaft 16. 'When the shaft `16 is thus mounted, its gear 19 is in mesh with the pinion gear 22 on the countershaft 23. lt will be .understood-that if other size shafts 16 having a larger gear 19 are used in lieu of the yillustrated shaft 16, the countershaft `23 may be moved toward or away from the other shafts `by.

provide correct mesh of the gears.

The grinder is rotated at a relatively fast speed in the clockwise direction indicated in Fig. 3, and the shaft 16 is driven in the same clockwise direction through the gear train including the gears 20, 21, 22, and 19. The headstock 14 is rotated in the same clockwise direction as the grinder 10 but at a much slower speed, and the shaft 16 is thus driven in the same direction through the gearing. When the workpiece 16 is being positioned between the headstock and tailstock, the grinder 10 is generally moved out of its illustrated position away from the workpiece 16, and once the workpiece is correctly mounted as just described, the grinder wheel 10, while rotating at a relatively fast speed is moved toward the shaft 16, so that the grinder wheel simultaneously grinds all of the various diameters on the shaft 16, with the shaft 16 being simultaneously driven at the relatively slow speed due to rotation of the headstock 14 and the motion transmitted through the gearing.

Utilizing the illustrated grinding apparatus, all of the diameters of the shaft 16 may be ground at the same time. Due to the use of the geary 19, the end diameter 43, for example, need not be utilized to be gripped within a collet or chuck for rotating the shaft 16 as it is being ground. It will be understood that the gear 19 actually has the prime purpose of transmitting power through the transmission in which the shaft 16 is eventually installed when'it is finished, and the gear 19 provides a convenient driving means for driving the shaft 16 in the illustrated grinding apparatus, this driving of the shaft 16 in the grinding operation by means of the gear 19 constituting an important secondary function for the gear 19. Since all of the diameters of the shaft 16 are simultaneously ground in a single operation, the eccentricity, small though it may be, that ordinarily occurs between the diameter of the shaft gripped by the collet or chuck and the remaining shaft diameters, utilizing the prior art methods in which the diameters are separately ground in two different operations, does not occur with our improved apparatus.

In addition to the above advantage of accomplishing the grinding of the shaft 16 in a single operation, it must be pointed out that the elimination of all the eccentricity that might occur in two grinding operations is an eX- tremely important step in the mass production of precision made parts. The reason being, that any eccentricity, even though minute, greatly increases the wear, thus resulting in reducing the life of the machine that the shaft would be incorporated in.

We Wish it to be understood that our invention is not to be limited to the specific constructions and arrangements shown and described except only insofar as the claims may be so limited as it will be understood to those skilled in the art that changes may be made without departing from the principles of the invention.

We claim:

1. An apparatus for grinding simultaneously a plurality of diameters on a workpiece having a gear Xed thereon, comprising a multi-diameter grinding wheel positioned by support means a headstock and a tailstock for mounting the workpiece, a gear connected to the headstock and a countershaft, said countershaft being formed with a gear on one end in mesh with the gear on the headstock and a gear on the other end in mesh with the gear on the workpiece, whereby said gear on the headstock drives the gear on the workpiece thus rotating the workpiece at the same speed of rotation as that of the headstock and permitting simultaneous grinding of all of said diameters on the workpiece in a single operation.

2. An apparatus for grinding simultaneously in one operation a plurality of diameters on a transmission shaft having a power transmitting gear integrally formed thereon, comprising a multi-diameter grinding wheel posimeans of the adjustments above described, inr order to,

tioned by support means, a headstock and a tailstock for mounting the transmission shaft, a gear on the headstock of the same size as the power transmitting gear, and a countershaft in parallel relationship with said transmission shaft, said countershaftbeing formed with a pinion gear on one end in mesh with the gear on the headstock and a pinion gear of the same size on the other end in mesh with the gear on the transmission shaft, whereby said gear on the headstock drives the gear on the transmission shaft thus rotating the transmission shaft at the same speed as that of the headstock as the shaft is being ground.

3. An apparatus for grinding simultaneously in one operation a plurality of diameters on a transmission shaft having a power transmitting gear fixed thereon comprising a multi-diameter grinding wheel positioned by support means, a headstock and a tailstock for rotatably positioning and mounting the transmission shaft in grinding relationship with said multi-diameter grinding wheel, a driving gear of the same size as said power transmitting gear and fixed to rotate with said headstock, a U-shaped support means, a countershaft rotatably supported by said support means, a rst pinion gear secured to one end of said countershaft and in mesh with said driving gear, and a second pinion gear secured to the other end of the countershaft in mesh with said power transmitting gear, whereby the drive from said driving gear is transmitted to the transmission shaft for rotating said shaft at the same speed as that of the headstock as the shaft is being ground.

4. A method of grinding in a single operation a transmission shaft having a power transmitting gear xed thereto, comprising the steps of rotatably mounting the shaft to be ground between a headstock and a tailstock, rotating said headstock, connecting said rotating headstock and said shaft for driving the shaft by means of .gearing including said gear on the shaft, and rotating a grinding wheel in grinding contact with said shaft at the same time as said headstock and thereby said transmission shaft are rotated.

5. A method of grinding simultaneously in a single operation a plurality of different diameters of a transmission shaft ,having a power transmitting gear fixed thereto, comprising the steps of rotatably mounting the shaft to be ground between a headstock and a tailstock, rotating said headstock, connecting said rotating headstock and said shaft for driving the shaft by means of gearing including said gear on the shaft for thereby rotating the shaft at a relatively low speed, and rotating a grinding wheel in grinding contact with said plurality of diameters of said shaft .and in the same directions as said shaft and at relatively high speed.

6. A method of grinding simultaneously in a single operation a plurality of different diameters of a transmission shaft having a power transmitting gear fixed thereto, comprising the steps of rotatably mounting the shaft to be ground between a headstock and a tailstock, rotating said headstock, drivingly connecting said transmission shaft with said headstock for driving the shaft by means of a gear fixed on said headstock and a countershaft having a pinion gear in mesh with said headstock gear and having a second pinion gear in mesh with said first-named gear, and rotating a multi-diameter grinding' wheel in grinding contact with said shaft diameters at the same time as said headstock and said transmission shaft are rotated.

References Cited in the file of this patent UNITED STATES PATENTS A Yeates Nov. 12, 1912 1,833,601 Batterman Nov. 24, 1931v 1,948,866 Norton Feb. 27 1934 2,006,724 Theler Iuly 2, 1935l 2,639,558 I -Cotchett Y 'May 26, Y 1953 

